As in any medical procedure, dental procedures require strict sanitary conditions guarding against contamination from patient-to-patient or from patient-to-dentist. As patients come and go through a series of examinations and procedures, the dentist must present to each patient sanitary conditions with respect to the environment of the examination and with respect to the equipment used during dental exam and dental procedures. The present invention concerns presentation of both sanitary environment and sanitary equipment to each new patient. More particularly, the present invention concerns dental handpiece systems maintained in sanitary condition and operated in such manner to prevent contamination of the surrounding environment.
Dental handpieces are air-driven devices. A common dental handpiece is the high-speed turbine drill. A turbine drill receives a flow of air along an air supply conduit for application against a rotatable turbine. As the air hits the turbine, it rotates the turbine and thereafter exits the handpiece by way of a return air conduit. Thus, dental handpieces are relatively lightweight devices coupled to a dental handpiece system by way of a set of air conduits. When in use the tool spins at approximately 350,000 rpm and develops a vortex or suction around the tool pulling debris, i.e., blood, saliva, or tooth material, into the handpiece in the vicinity of the turbine. More particularly, typical handpiece construction leaves open the handpiece housing in the vicinity of the turbine bearings. Due to the increased air velocity, and therefore reduced air pressure, debris in the vicinity of the tool moves into the handpiece housing. Accordingly, debris moves into the return air conduit and back into the system delivery unit and eventually into the exhaust system. Because such return air has not traditionally been managed with respect to bio-contamination, such exhaust air typically enters directly back into the ambient air of the dental operating room.
While not well recognized as a significant hazard to patients, dentists, and staff, such untreated release of bio-contaminants represents risk to those in the dental operating room. This becomes especially hazardous where such contaminants remain in place for long periods resulting in growth of hazardous mold and fungus. Thus, contamination becomes serious when debris collected by the handpieces rests for extended periods within the handpiece system delivery unit. Occasional maintenance or repair requiring opening of the delivery unit exposes the maintenance or repair person to significant biohazard. Without strict attention to proper cleanup procedures, such contamination can spread further into the operating room environment during maintenance, repair, or cleanup. Generally, such accumulated biohazard and resulting mold and fungus represent an undesirable presence in any medical environment.
According to one method of treatment, the return air tubes connect together to a common discharge and the debris collects in a gauze pad. Thus, where this method does collect some of the debris carried away from the procedure site, there remains significant contamination in the form of atomized bio-contaminants not captured in the gauze trap and, therefore, entering the ambient air of the dental examination room. When the gauze impedes airflow from the common discharge, a backpressure exists at the terminal portions, i.e., at the common discharge, and, undesirably, airflow passes in the reverse direction along such return air conduits, i.e., passes in the direction of the handpiece. This represents a significant opportunity for bio-contamination of other handpieces as well as the operating room environment.
A second method filters directly at the handpiece, i.e., places in-line a filter along the both the supply and return air conduit at the handpiece. Unfortunately, this should require a filter change for every use. Also, it must be replaced for every patient, it adds additional weight at the handpiece, and it finds application for only a limited set of handpiece types.
U.S. Pat. No. 5,897,317 issued Apr. 27, 1999 and entitled Dental Handpiece With Disposable Filter Cartridge, shows placement of a filter cartridge at the handpiece for cleaning drive air, water, chip air, and exhaust passing through the handpiece. U.S. Pat. No. 5,716,210 issued Feb. 10, 1998 and entitled Disposable Filter For Dental Handpiece also illustrates an insert placed in line at the handpiece for filtering air and water. U.S. Pat. No. 5,749,726 issued May 12, 1998 and entitled Disposable Point Of Use Filtration Element For Purifying Air And Water Supplies To Dental Handpieces also illustrates an in-line proposition for filtration at a dental handpiece relative to cooling water and cooling air supplies but unrestricted turbine supply and return air.
U.S. Pat. No. RE30,340 reissued Jul. 22, 1980 and entitled Dental Handpiece attempts to avoid collection of bio-contaminants at the handpiece by restricting the fluid outlet from the turbine sufficiently to ensure that a portion of the fluid is exhausted through the turbine bearings and openings in the housing to prevent ergots of foreign matter into the interior. Restricting airflow at the downstream side of the turbine, however, impedes turbine performance and, therefore, impedes overall efficiency of the dental handpiece. Furthermore, this proposition undesirably blows excess air into the patient""s mouth.
U.S. Pat. No. 5,318,443 issued Jun. 7, 1994 and entitled Method Of Flushing Disinfecting And Lubricating A Dental Turbine Handpiece illustrates a mechanism by which a handpiece may be flushed clean of contaminants while not in operation. Unfortunately, the proposed solution does not address concerns relating to the collection and discharge of bio-contaminants during operation.
The xe2x80x9csaliva ejectorxe2x80x9d, i.e., a separate device pulling by vacuum material from the patient""s mouth during a procedure, removes excess fluid from the operating site. This system carries the bulk of material away from the site and is well recognized as a source of potential bio-contamination. Some saliva ejector systems filter the return air and deposit the waste into the public sewer. U.S. Pat. No. 5,571,412 issued Nov. 5, 1996 and entitled Dental Filter Assembly illustrates a filter canister assembly receiving waste from a dental cuspidor.
Filtration systems have also been applied in-line relative to water supply lines. For example, U.S. Pat. No. 5,971,757 issued Oct. 26, 1999 and entitled In-Line Filter System For Dental Instruments illustrates a filter unit placed in-line relative to a water supply line for a dental instrument.
Need remains, however, to improve dental handpiece systems to manage better the relatively smaller volume, e.g., in relation to the saliva ejector system, debris inadvertently collected at the handpiece. More particularly, there remains need to reduce the risk of contamination to the doctor, patient, and staff as a result of debris carried by the dental handpiece and potentially accumulating within the dental handpiece delivery unit.
The present invention addresses this and other concerns with management of bio-contamination relative to dental handpieces and dental handpiece systems.
In accordance with the present invention, an exhaust manifold for a dental handpiece system receives at an inlet thereof return air flow provided by a dental handpiece. A unidirectional valve couples the inlet to a common manifold space which in turn couples to ambient air by way of a filter. By applying filtration on the backside of the unidirectional valve, air entering the common manifold space cannot thereafter reenter the return air conduit and thereby contaminate the same handpiece or other handpieces in a multiple handpiece system.
As applied in a multiple handpiece system, the exhaust manifold under the present invention includes a plurality of inlets each corresponding to and receiving the return air from a corresponding handpiece. Each inlet in turn couples by way of a corresponding unidirectional valve to the common manifold space. The common manifold space in turn couples to ambient air via a filter. Back pressure produced at the filter relative to the common manifold space cannot reintroduce air back into any of the return air supply conduits because the corresponding unidirectional valves block such air flow.
The filter unit as proposed under the present invention is removeably mounted and thereby replaceable when needed. Frequent replacement of the filter unit protects against undesirable accumulation of bio-contaminants and growth of microorganisms thereupon.
Ambient air within the dental examination area is thereby protected against contamination as well all dental handpieces within a dental handpiece system protected against contamination relative to bio-contaminants and oil originating from a given handpiece.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation of the invention, together with further advantages and objects thereof, may best be understood by reference to the following description taken with the accompanying drawings wherein like reference characters refer to like elements.